Wake vortices that form behind a moving aircraft represent 11 safety COil cern for other aircraft.s that follow. These tornado-like wake structures may persist for several minutes, extending for many kilometers across the sky. This safety issue is particularly important close to major airports where successive aircrafts follow approximately the same approach or departure paths at relatively high frequency. For this reason, safety regulations require aircrafts to be well separated in flight. This obviously limits the airport's throughput capacity, even to the point of leading to congestion and delays.